Found an HKU\S-1-5-21 registry key malware, what do I do? [ Edited ]

[#1]

I found an HKU\S-1-5-21 in my pc, its currently being quarantined, I deleted it, restarted my PC and they found it again.

Also on my adwcleaner they found a C:\END file that's currently in quarantine.

What are my next steps? How do I remove the virus from my PC? It's been slowing down a lot.

Also, I found another file called evernote uninstall but im not sure if this is a virus, tho i deleted it also.